Plasma processing apparatus

Abstract

The plasma processing apparatus includes: a processing chamber disposed inside a vacuum vessel; a first high-frequency power supply outputting a first high-frequency power for supplying an electric field to generate a plasma for use in processing a sample to be processed inside the processing chamber; a sample stage disposed inside the processing chamber with the sample placed on an upper surface thereof; a second high-frequency power supply intermittently outputting a second high-frequency power for generating a bias potential to an electrode disposed inside the sample stage and capable of variably adjusting the output time; and a function to adjust operation of the plasma processing apparatus using a result of detection of a temporal change in waveform of current or voltage in a transient state of the second high-frequency power in synchronism with start of the intermittent output of the second high-frequency power.

The invention claimed is: 
     
       1. A plasma processing apparatus comprising:
 a processing chamber disposed inside a vacuum vessel; 
 a first high-frequency power supply outputting a first high-frequency power for supplying an electric field to generate a plasma for use in processing a sample to be processed inside the processing chamber; 
 a sample stage disposed inside the processing chamber, on an upper surface of which the sample is placed; 
 a second high-frequency power supply intermittently outputting a second high-frequency power for generating a bias potential to an electrode disposed inside the sample stage so that a waveform of the second high-frequency power is synchronized with a reference cyclical signal and capable of variably adjusting the output time, and 
 a controller configured to adjust operation of the plasma processing apparatus using a result of detection of a temporal change in a waveform of current or voltage in a transient state of the second high-frequency power, the temporal change in the waveform in the transient state of the second high-frequency power being synchronized with a start of the intermittent output of the second high-frequency power and being detected by comparing, with each other, a plurality of waveforms of current or voltage which are detected in a predetermined time length in the transient state of the second high-frequency power. 
 
     
     
       2. The plasma processing apparatus according to  claim 1 , wherein
 the temporal change in waveform of current or voltage in the transient state of the second high-frequency power is detected while synchronized with the reference cyclical signal. 
 
     
     
       3. The plasma processing apparatus according to  claim 1 , wherein
 the temporal change in the waveform is detected by comparing the plurality of waveforms of current or voltage with each other, among the plurality of waveforms in a predetermined time length in the transient state of the second high-frequency power, the phases of the plurality of waveforms being aligned with each other. 
 
     
     
       4. The plasma processing apparatus according to  claim 1 , wherein
 stop of the plasma processing apparatus or change of the processing condition is conducted using a result of detection of the temporal change in waveform of current or voltage in the transient state of the second high-frequency power. 
 
     
     
       5. The plasma processing apparatus according to  claim 1 , wherein
 the waveform of the second high-frequency power is detected at every predetermined time interval in the transient state. 
 
     
     
       6. The plasma processing apparatus according to  claim 1 ,
 wherein the controller is further configured to detect the temporal change in the waveform by determining a time from generation of a self-bias voltage to a transition to a steady state of said waveform in which positive and negative components are substantially symmetrical. 
 
     
     
       7. A plasma processing apparatus comprising:
 a processing chamber disposed inside a vacuum vessel; 
 a first high-frequency power supply outputting a first high-frequency power for supplying an electric field to generate plasma for use in processing a sample to be processed inside the processing chamber; 
 a sample stage disposed inside the processing chamber, on an upper surface of which the sample is placed; 
 a second high-frequency power supply outputting a second high-frequency power for generating a bias potential to an electrode disposed inside the sample stage so that a waveform of the second high-frequency power is synchronized with a reference cyclical signal and capable of variably adjusting ON time and OFF time of the output or a ratio thereof, and 
 a controller configured to adjust operation of the plasma processing apparatus using a result of detection of a temporal change in waveform of current or voltage in a transient state of the second high-frequency power, the temporal change in the waveform in the transient stage of the second high-frequency power being synchronized with a start of an ON period of the second high-frequency power and being detected by comparing, with each other, a plurality of waveforms of current or voltage which are detected in a predetermined time length in the transient state of the second high-frequency power. 
 
     
     
       8. The plasma processing apparatus according to  claim 7 , wherein
 the temporal change in waveform of current or voltage in the transient state of the second high-frequency power is detected while synchronized with the reference cyclical signal. 
 
     
     
       9. The plasma processing apparatus according to  claim 7 ,
 wherein the temporal change in the waveform is detected by comparing the plurality of waveforms of current or voltage with each other, among the plurality of waveforms in a predetermined time length in the transient state of the second high-frequency power, the phases of the plurality of waveforms being aligned with each other. 
 
     
     
       10. The plasma processing apparatus according to  claim 7 ,
 wherein stopping of the plasma processing apparatus or changing of the processing condition is conducted using a result of detection of the temporal change in waveform of current or voltage in the transient state of the second high-frequency power. 
 
     
     
       11. The plasma processing apparatus according to  claim 7 ,
 wherein the controller is further configured to detect the temporal change in the waveform by determining a time from generation of a self-bias voltage to a transition to a steady state of said waveform in which positive and negative components are substantially symmetrical.